I've been doing some mystery shopping on and off now for about a year now and LOVE it! It's great that you feel like you opinion about service is actually being heard. I would not do any type of MS through an email because there are
TONS of sites out there that you can sign up for free. One thing that's great about it is that you can pick your own schedule. If your busy the day they need it done, then don't sign up for the shop. The only down side is usually you have to pay upfront for any products/services then depending on the company it could be between two to six weeks to receive payment. You aren't going to get rich off of MS but there are many different fun activities that you can get paid to do. I've eaten some
really nice meals on someone else's tab, been asked to go bowling, my sister in law lives in an area where one can do hotel shops (where they pay for so many nights for you and someone else in a hotel room). Some companies I've seen will pay for your carpets to be cleaned, or you to get fresh flowers delivered to your house or business. Anyway, there are tons of things out there. I've been advised to stay away from apartment shops because the forms one has to fill out are really long compared to the pay one receives. However, sometimes for me it's not always about the pay I will receive, it's about where I get to go ... Like my sister in law was compensated up to $60 for lunch or $150 for dinner at a restaurant shop, it didn't pay anything on top of the meal but this was a place that her and her husband would not usually be able to afford to eat so she accepted it.
To sign up for MS, one great website to go to is
www.volition.com they have a tab that says "get paid" then a link that says "get paid for shopping." This link will bring up many, many, many MS companies that you can sign up for free. Some are better than others, but you might want to check their forums to see what others are saying about the companies. Also, some only service particular areas. I signed up for a different email account through yahoo separate from the one I usually use, because I wasn't sure about the spam factor just to play it safe.
I hope I answered all of your questions! If I missed something, please let me know, or if something else comes to mind I don't mind trying to answer!